This disclosure generally relates to systems and methods for supporting an airplane in order to facilitate the repair or replacement of airplane parts.
Many existing shoring practices for repairing and/or replacing parts of an airplane require that support equipment such as body cradles be disposed against various portions of the airplane, and additionally require the use of support equipment comprising horizontal stabilizing units. This support equipment is used to support the airplane via the airplane's airframe structure in order keep the airplane off of the ground to facilitate maintenance tasks. In these existing shoring practices, the rigidity of the airplane is primarily dependent upon the airframe structure. For this reason, there is a limit to the amount of airframe structure that can be removed simultaneously. Exceeding these limits will result in deformation and overload of the airframe, which will render the airplane un-airworthy. Often, due to airplane constraints and/or loading limits, additional load bearing supports at other locations are not allowed. When lower fuselage skin panels are replaced, stabilizing beams are often extended through the airplane's windows to allow the cradles to be removed in order to gain access to the lower skin panels.
An apparatus and/or method for supporting an airplane should maintain the rigidity required to avoid overloading the remaining airframe structure, the required airframe alignment, and the structural integrity, strength, and airworthiness requirements. Typical jacking and shoring solutions include: 1) jacking from structural jack points manufactured on the airplane; 2) using contoured body cradles contacting and lifting on the lower portion of the fuselage; 3) installing window beams that interface with the structural window forgings that are common to most aircraft. Another solution is to support the airplane alignment via the airplane's floor structure. In particular, U.S. Pat. No. 8,393,598 discloses a shoring apparatus (described in more detail below with reference to FIGS. 1 and 2) comprising a plurality of beams disposed underneath an airplane floor structure within the airplane, and one or more jacks supporting the beams.
Generally, if the airplane has sustained damage on the lower portion of the fuselage, the repair personnel must jack and support the airplane at an elevation above the location of the damage to be repaired. Traditional aircraft having fuselages not made of composite material have heavy, structural window forgings that surround each window interior. Each window forging is configured to mate with the airframe of the aircraft. It is known to pass a structural I-beam through the window and use a special nest block to transmit load to the window forging and support the aircraft there. The drawbacks of this technique are the fuselage skins then take the load, but for the most part, this method is sufficient. However, an airplane having a fuselage made of composite material (e.g., carbon fiber reinforced plastic) has no such window forging, and does not have the structural integrity to carry any type of jacking load through the skin from this location.
There is a continuing demand for improvements in systems and methods for supporting an airplane.